Dynamic testing based on thermal and stress conditions

Abstract

A plurality of sets of test conditions of a die in a stacked system is established, wherein the plurality of test conditions are functions of temperatures of the die, and wherein the stacked system comprises a plurality of stacked dies. A temperature of the die is measured. A respective set of test conditions of the die is found from the plurality of sets of test conditions, wherein the set of test conditions corresponds to the temperature. The die is at the temperature using the set of test conditions to generate test results.

What is claimed is: 
     
       1. A method comprising:
 establishing a plurality of sets of test conditions of a first die in a stacked package, wherein the plurality of test conditions are functions of temperatures of the first die, and wherein the stacked package comprises a plurality of stacked dies; 
 measuring a first temperature of the first die; 
 finding a respective set of test conditions of the first die from the plurality of sets of test conditions, wherein the set of test conditions corresponds to the first temperature; and 
 testing the first die at the first temperature using the set of test conditions to generate test results. 
 
     
     
       2. The method of  claim 1  further comprising:
 establishing a dynamic pass/fail specification of the first die, wherein the dynamic pass/fail specification is a function of temperatures of the first die; 
 finding a pass/fail criteria of the first die from the dynamic pass/fail specification, wherein the pass/fail criteria corresponds to the first temperature; and 
 comparing the test results with the pass/fail criteria to determine a pass/ fail status of the first die. 
 
     
     
       3. The method of  claim 2 , wherein the dynamic pass/fail specification of the first die is a function of a stress in the first die, and wherein the method further comprises:
 measuring a stress of the first die at the first temperature, wherein the pass/fail criteria of the first die further corresponds to the stress of the first die. 
 
     
     
       4. The method of  claim 1  further comprising, before the steps of measuring the first temperature of the first die and testing the first die, testing a second die in the stacked package, wherein between the step of testing the second die and the step of measuring the first temperature, the temperature of the first die is not changed. 
     
     
       5. The method of  claim 1 , wherein the step of establishing the plurality of sets of test conditions of the first die comprises establishing a lookup table comprising a plurality of temperature ranges, each corresponding to one of the plurality of sets of test conditions. 
     
     
       6. The method of  claim 5 , wherein the lookup table further comprises a plurality of dynamic specifications different from each other, wherein each of the dynamic specifications corresponds to one of the plurality of temperature ranges, and wherein the plurality of dynamic specifications is selected from the group consisting essentially of a current specification, a voltage specification, a frequency specification, a power consumption specification, DC parameter specifications, and combinations thereof. 
     
     
       7. The method of  claim 1 , wherein the stacked package further comprises a second die, and wherein the plurality of test conditions are functions of temperatures of the first die and the second die. 
     
     
       8. The method of  claim 7  further comprising:
 establishing dynamic pass/fail specifications of the first die and the second die, wherein the dynamic pass/fail specifications are functions of the temperatures of the first die and the second die; 
 measuring a second temperature of the second die, wherein the set of test conditions comprises joint test conditions of the first die and the second die, and wherein the set of test conditions corresponds to the first temperature of the first die and the second temperature of the second die; and 
 testing the second die using the set of test conditions. 
 
     
     
       9. The method of  claim 8 , wherein the dynamic pass/fail specifications of the first die and the second die are further functions of stresses in the first die and the second die. 
     
     
       10. A method comprising:
 establishing a dynamic pass/fail specification of a first die in a package, wherein the dynamic pass/fail specification is a function of temperatures of the first die, and wherein the package comprises a plurality of stacked dies; 
 measuring a first temperature of the first die; 
 finding a pass/fail criteria of the first die corresponding to the first temperature; 
 testing the first die at the first temperature to generate test results; and 
 comparing the test results with the pass/fail criteria to determine a pass/fail status of the first die. 
 
     
     
       11. The method of  claim 10  further comprising:
 establishing a plurality of sets of test conditions of the first die, wherein the plurality of test conditions is functions of the temperatures of the first die; and 
 finding a respective set of test conditions of the first die from the plurality of sets of test conditions, wherein the set of test conditions corresponds to the first temperature, and wherein the step of testing the first die is performed using the set of test conditions. 
 
     
     
       12. The method of  claim 11 , wherein the dynamic pass/fail specification of the first die is further a function of a stress in the first die, and wherein the method further comprises:
 measuring a stress of the first die at the first temperature, wherein the pass/fail criteria of the first die corresponds to the stress of the first die. 
 
     
     
       13. The method of  claim 10  further comprising, before the steps of measuring the first temperature of the first die and testing the first die, testing a second die in the package, and wherein between the step of testing the second die and the step of measuring the first temperature, the temperature of the first die is substantially not changed. 
     
     
       14. The method of  claim 10 , wherein the step of establishing the dynamic pass/fail specification of the first die comprises establishing a lookup table comprising a plurality of temperature ranges, each corresponding to one of a plurality of dynamic pass/fail specifications. 
     
     
       15. The method of  claim 14 , wherein the lookup table further comprises a plurality of sets of test conditions different from each other, wherein each of the plurality of sets of test conditions corresponds to one of the plurality of temperature ranges. 
     
     
       16. The method of  claim 10 , wherein the package further comprises a second die, and wherein the dynamic pass/fail specification is a function of temperatures of the first die and the second die. 
     
     
       17. A method comprising:
 providing a first and a second package identical to each other, wherein the first package comprises a first die identical to a second die in the second package; 
 heating the first die by heating a first prober chuck attached to the first package to a target temperature; 
 heating the second die by heating a second prober chuck attached to the second package to the target temperature; 
 measuring a first temperature of the first die when the first prober chuck is at the target temperature; 
 measuring a second temperature of the second die when the second prober chuck is at the target temperature, wherein the first temperature is different from the second temperature; 
 finding a first set of test conditions from a lookup table storing test conditions as functions of temperatures, wherein the first set of test conditions corresponds to the first temperature; 
 finding a second set of test conditions from the lookup table, wherein the second set of test conditions corresponds to the second temperature, and is different from the second set of test conditions; 
 testing the first die using the first set of test conditions to generate first test results; and 
 testing the second die using the second set of test conditions to generate second test results. 
 
     
     
       18. The method of  claim 17 , wherein the lookup table comprises a plurality of temperature ranges corresponding to a plurality of sets of test conditions, wherein the plurality of temperature ranges are in different rows or columns of the lookup table. 
     
     
       19. The method of  claim 17 , wherein the lookup table further comprises dynamic pass/fail specifications of dies expressed as functions of temperatures. 
     
     
       20. The method of  claim 19 , wherein the dynamic pass/fail specifications of the dies are further expressed as functions of stresses in the dies.